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A researcher is curious to see if stress level for high school students influences their likelihood of going to college.  So they ask 500 people who attended college what their stress level was in high school and asked 500 people who did not attend college what their stress level was in high school.  What type of study design is this?

A study is observational when the researcher controls the behaviors of their subjects.

If a researcher is given a list of all 51,000 students that go to the university and each student has a 10% chance of being selected to participate in the study, what type of sampling has occurred?

A study is experimental when the researcher lets things happen naturally.

The 50th percentile is also know as what?

It is known that people in the USA spend on average 18 hours a day using electronic devices with a standard deviation of 5.8 hours. This data follows a normal distribution. What is the probability someone spends less than 13 hours using electronic devices a day? (round your answer to 4 decimals)

Select the best description of IQR.

A variable measured someone’s stress level, the variable has the following values: Not stressed at all, only a little stressed, stressed, and very stressed.   This variable type is [Answer1] This variable’s categorization is [Answer2]

It is known that people in the USA spend on average 17 hours a day using electronic devices with a standard deviation of 7 hours.  This data follows a normal distribution.  What is the probability someone spends exactly 17 hours using electronic devices a day? (round your answer to 4 decimals)

A variable measured the acidic/base balance of a liquid on the pH scale.  The pH scale exists on a range from 0 (extremely acidic) to 14 (extremely basic).   This variable type is [Answer1] This variable’s categorization is [Answer2]